In fabricating integrated circuits, semiconductor chips and the like, chemical/mechanical planarization can be used as an intermediate operation to planarize a structure to provide a uniform, level surface for subsequent processing operations in the manufacturing of a semiconductor chip or integrated circuit. For example, electrodes or electrical contacts between different layers of conductive materials in a semiconductor chip can be formed by depositing a first layer of conductive material, typically a metal, although a semiconductor material could be used as well, and then depositing a thin dielectric layer over the first conductive layer. The dielectric layer is then patterned to form at least one opening in the dielectric layer to expose a portion of the surface of the first conductive layer. The opening can have a small aspect ratio of depth to width. For instance, the opening can be about half a micron wide but only about 500 angstroms deep thus presenting a aspect ratio of about 0.1. A second layer of a different conductive material is then deposited on the dielectric layer and in the opening on the first conductive layer to make electrical contact through the opening with the first conductive layer. The second conductive layer is then removed form the dielectric layer or planarized to expose the dielectric layer and to form an isolated electrode or damascene contact structure in the opening before subsequent fabrication operations. In removing the second conductive layer by chemical/mechanical processing or planarization (CMP), the forces created by the CMP process can have a tendency to force the conductive material of the second layer out of the opening thereby destroying the contact.
Accordingly, for the reason stated above, and for other reasons that will become apparent upon reading and understanding the present specification, there is a need for an electrode structure and method of fabrication that provides substantially improved adhesion between a first layer of conductive material and second layer of a different conductive material, particularly during a CMP operation, and that does not adversely effect the conductivity between the two layers or create an electrical barrier. There is also a need for a method of fabricating an electrode structure that does not effect or damage other components that may already have been formed on the same wafer or substrate and that does not adversely effect the manufacturing process by requiring a significant number of additional process operations.